This paper summarizes the results of aging, condition monitoring, and accident testing of Class 1E cables used in nuclear power generating stations. Three sets of cables were aged for up to 9 months under simultaneous thermal ({approximately}100{degrees}C) and radiation ({approximately}0.10 kGy/hr) conditions. After the aging, the cables were exposed to a simulated accident consisting of high dose rate irradiation ({approximately}6 kGy/hr) followed by a high temperature steam (up to 400{degrees}C) exposure. A fourth set of cables, which were unaged, was also exposed to the accident conditions. The cables that were aged for 3 months and then accident tested were subsequently exposed to a high temperature steam fragility test (up to 400{degrees}C), while the cables that were aged for 6 months and then accident tested were subsequently exposed to a 1000-hour submergence test in a chemical solution. The results of these tests do not indicate any reason to believe that many popular nuclear power plant cable products cannot inherently be qualified for 60 years of operation for conditions simulated by this testing. Mechanical measurements (primarily elongation, modulus, and density) are more effective than electrical measurements for monitoring age-related degradation. In the high temperature steam test, ethylene propylene rubber (EPR) cable materials generally survived to higher temperatures than crosslinked polyolefin (XLPO) cable materials. In dielectric testing after the submergence testing, the XLPO materials performed better than the EPR materials.
This paper describes several different types of constraints that can be placed on multilayered feedforward neural networks which are used for automatic target recognition (ATR). We show how unconstrained networks are likely to give poor generalization on the ATR problem. We also show how the ATR problem requires a special type of classifier called a one-class classifier. The network constraints come in two forms: architectural constraints and learning constraints. Some of the constraints are used to improve generalization, while others are incorporated so that the network will be forced to perform one-class classification. 14 refs
Foams, like most highly structured fluids, exhibiting rheological behavior that is both fascinating and complex. We have developed microrheological models for uniaxial extension and simple shearing flow of a dry', perfectly ordered, three-dimensional foam composed of thin films with uniform surface tension T and negligible liquid content. We neglect viscous flow in the thin films and examine large elastic-plastic deformations of the foam. The primitive undeformed foam structure is composed of regular space-filling tetrakaidecahedra, which have six square and eight hexagonal surfaces. This structure possesses the film-network topology that is necessary to satisfy equilibrium: three films meet at each edge, which corresponds to a Plateau border, and four edges meet at vertex. However, to minimize surface energy, the films must meet at equal angles of 120{degrees} and the edges must join at equal tetrahedral angles of cos{sup {minus}1}({minus}1/3) {approx} 10.947{degree}. No film in an equilibrium foam structure can be a planar polygon because no planar polygon has all angles equal to the tetrahedral edge. In the equilibrium foam structure known as Kelvin's minimal tetrakaidecahedron, the squares' are planar quadrilateral surfaces with curved edges and the hexagons' are non-planar saddle surfaces with zero mean curvature. As the foam structure evolves with the macroscopic flow, each film maintains zero mean curvature because the pressure is the same in every bubble. In general, the shape of each thin film, defined by z = h(x,y), satisfies R{sub 1}/1 + R{sub 2}/1 = {del}{center dot} (1 + {vert bar}{del}h{vert bar}){sup {1/2}} = O where R{sub 1}{sup {minus}1} and A{sub 2}{sup {minus}1} are the principal curvatures. The appropriate boundary conditions correspond to three films meeting at equal angles. For the homogeneous deformations under consideration, the center of each film moves affinely with the flow. 5 refs
Renewable energy technologies convert naturally occurring phenomena into useful energy forms. These technologies use resources that generally are not depleted, such as the direct energy (heat and light) from the sun and the indirect results of its impact on the earth (wind, falling water, heating effects, plant growth), gravitational forces (the tides), and the heat of the Earth's core (geothermal), as the sources from which they produce useful energy. These very large stores of natural energy represent a resource potential that is incredibly massive -- dwarfing that of equivalent fossil energy resources. The magnitude of these resources is, therefore, not a key constraint on energy production. However, they are generally diffuse and not fully accessible, some are intermittent, and all have distinct regional and local variability. It is these aspects of their character that give rise to difficult, but generally solvable, technical, institutional, and economic challenges inherent in development and use of renewable energy resources. This report discusses the technologies and their associated energy source.
Theoretical models have been formulated describing the dynamic behavior of the swelling and contracting of polyelectrolyte gels. This paper presents a method of weighted residuals approach to solving the governing system of equations by finite element analysis. The modulation of the imbibition of solvent by a spherical gel is studied.
There is considerable interest in the use of chemically vapor deposited (CVD) polycrystalline diamond films in advanced materials technology. However, most of the potential applications of CVD diamond films require well-controlled properties which depend on the film structure, and in turn, on the conditions under which the films are synthesized. The structure of the vapor-deposited diamond films is frequently characterized by Raman spectroscopy. Despite extensive research, much work still needs to be completed to understand the various features of the Raman spectra and to understand how the processing variables affect the spectral features. This paper examines the Raman spectra of diamond films prepared by a hot-filament-assisted CVD process as a function of substrate processing and deposition parameters.
Many applications of national importance require the design, analysis, and simulation of complex electromagnetic phenomena. These applications range from the simulation of synthetic aperture radar to the design and analysis of low-observable platforms, antenna design, and automatic target recognition. In general, the modeling of complex electromagnetic phenomena requires significant amounts of computer time and capacity on conventional vector supercomputers but takes far less on massively parallel computers. Sandia National Laboratories is currently developing massively parallel methods and algorithms for the characterization of complex electromagnetic phenomena. The goal of on going research at Sandia is to understand the characteristics, limitations, and trade-offs associated with complex electromagnetic systems including: modeling the seeker response to complex targets in clutter, calculating the radiation and scattering from conformal communication and radar system antennas, and the analysis and design of high speed circuitry. By understanding the theoretical underpinnings of complex electromagnetic systems it is possible to achieve realistic models of system performance. The first objective is the development of computationally practical, high fidelity, systems models targeted for massively parallel computers. Research to achieve this objective is conducted in such areas as mathematical algorithms, problem decomposition, inter-processor communication schemes, and load balancing. The work in mathematical algorithms includes both the development of new methods and the parallel implementation of existing techniques. The second objective is the application of these high fidelity models to facilitate a better understanding of systems level performance for many C{sup 3}I platforms. This presentation describes applications of much current interest and novel solution techniques for these applications utilizing massively parallel processing techniques.
A neighboring external control problem is formulated for a hypersonic glider to execute a maximum-terminal-velocity descent to a stationary target. The resulting two-part, feedback control scheme initially solves a nonlinear algebraic problem to generate a nominal trajectory to the target altitude. Secondly, a neighboring optimal path computation about the nominal provides a lift and side-force perturbations necessary to achieve the target downrange and crossrange. On-line feedback simulations of the proposed scheme and a form of proportional navigation are compared with an off-line parameter optimization method. The neighboring optimal terminal velocity compares very well with the parameter optimization solution and is far superior to proportional navigation. 8 refs.
This paper describes the design of an inverse adaptive filter, using the Least-Mean-Square (LMS) algorithm, the correct data taken with an analog filter. The gradient estimate used in the LMS algorithm is based upon the instantaneous error, e{sup 2}(n). Minimizing the mean-squared-error does not provide an optimal solution in this specific case. Therefore, another performance criterion, error power, was developed to calculate the optimal inverse model. Despite using a different performance criterion, the inverse filter converges rapidly and gives a small mean-squared-error. Computer simulations of this filter are also shown in this paper.
Intense light ion beams are being developed to drive inertial confinement fusion (ICF) targets. Recently, intense proton beams have been used to drive two different types of targets in experiments on the Particle Beam Fusion Accelerator. The experiments focused separately on ion deposition physics and on implosion hydrodynamics. In the ion deposition physics experiments, a 3--4 TW/cm{sup 2} proton beam heated a low-density foam contained within a gold cylinder with a specific power deposition exceeding 100 TW/gm for investigating ion deposition, foam heating, and generation of x-rays. The significant results from these experiments included the following: the foam provided an optically thin radiating region, the uniformity of radiation across the foam was good, and the foam tamped the gold case, holding it in its original position for the 15 ns beam pulse width.
This document describes the Temperature Monitoring System for the RHEPP project at Sandia National Laboratories. The system is designed to operate in the presence of severe repetitive high voltage and electromagnetic fields while providing real time thermal data on component behavior. The thermal data is used in the design and evaluation of the major RHEPP components such as the magnetically switched pulse compressor and the linear induction voltage adder. Particular attention is given to the integration of commercially available hardware and software components with a custom written control program. While this document is intended to be a reference guide, it may also serve as a template for similar applications. 3 refs.
This bibliography contains 34 references concerning utilizing benchmarking in the management of businesses. Books and articles are both cited. Methods for gathering and utilizing information are emphasized. (GHH)
Measurements have recently been conducted and computer models constructed to determine the coupling of lightning energy into munition storage bunkers as detailed in companion conference papers. In this paper transfer functions from the incident current to the measured parameters are used to construct simple circuit models that explain much of the important observed quantitative and qualitative information and differences in transfer functions are used to identify nonlinearities in the response data. In particular, V{sub oc} -- the open-circuit voltage generated between metal objects in the structure, I{sub sc} -- the short-circuit current generated in a wire connecting metal objects in the structure, and a typical current measurement in the buried counterpoise system behave in a relatively simple manner explainable by one or several circuit elements. The circuit elements inferred from measured data are comparable in magnitude with those developed from simple analytical models for inductance and resistance. These analytical models are more useful in predicting bounding electromagnetic environment values rather than providing exact time domain waveforms. 2 refs.
The restoration of environmentally contaminated sites at DOE facilities has become a major effort in the past several years. The variety of wastes involved and the differing characteristics have driven the development of new restoration and monitoring technologies. One of the new remediation technologies is being demonstrated at the Savannah River Site near Aiken, South Carolina. In conjunction with this demonstration, a new technology for site characterization and monitoring of the remediation process has been applied by Sandia National Laboratories.
We used surface-profile data taken with a noncontact laser profilometer to determine the aperture distribution within a natural fracture and found the surfaces and apertures to be isotropic. The aperture distribution could be described equally well by either a normal or a lognormal distribution, although we had to adjust the standard deviation to 'fit' the data. The aperture spatial correlation varied over different areas of the fracture, with some areas being much more correlated U= others. The fracture surfaces did not have a single fractal dimension over all length scales, which implied that they were not self-similar. We approximated the saturated flow field in the fracture by solving a finite-difference discretization of the fluid-flow continuity equation in two dimensions. We then calculated tracer breakthrough curves using a particle-tracking method. comparing the breakthrough curves obtained using both coarse- and fine-resolution aperture data (0.5- and 0.05-mm spacing between points, respectively) over the same subset of the fracture domain suggests that the spacing between the aperture data points must be less than the correlation length to obtain accurate predictions of fluid flow and tracer transport. In the future, we will perform tracer experiments and numerical modeling studies to determine exactly how fine the aperture data resolution must be (relative to the correlation length) to obtain accurate predictions.
Sandia National Laboratories (SNL) designs, tests and operates a variety of accelerators that generate large amounts of high energy Bremsstrahlung radiation over an extended time. Typically groups of similar accelerators are housed in a large building that is inaccessible to the general public. To facilitate independent operation of each accelerator, test cells are constructed around each accelerator to shield it from the radiation workers occupying surrounding test cells and work-areas. These test cells, about 9 ft. high, are constructed of high density concrete block walls that provide direct radiation shielding. Above the target areas (radiation sources), lead or steel plates are used to minimize skyshine radiation. Space, accessibility and cost considerations impose certain restrictions on the design of these test cells. SNL Health Physics division is tasked to evaluate the adequacy of each test cell design and compare resultant dose rates with the design criteria stated in DOE Order 5480.11. In response SNL-Health Physics has undertaken an intensive effort to asses existing radiation shielding codes and compare their predictions against measured dose rates. This paper provides a summary of the effort underway and its results.
The last decade has offered many challenges to the welding metallurgist: new types of materials requiring welded construction, describing the microstructural evolution of traditional materials, and explaining non-equilibrium microstructures arising from rapid thermal cycle weld processing. In this paper, the author will briefly review several advancements made in these areas, often citing specific examples of where new insights were required to describe new observations, and to show how traditional physical metallurgy methods can be used to describe transformation phenomena in advanced, non-traditional materials. The paper will close with comments and suggestions as to the needs required for continued advancement in the field.
Phase II of the Long Valley Exploratory Well was completed to a depth of 7588 feet in November 1991. The drilling comprised two sub-phases: (1) drilling 17-1/2 inch hole from the Phase I casing shoe at 2558 feet to a depth of 7130 feet, plugging back to 6826 feet, and setting 13-3/8 inch casing at 6825 feet, all during August--September 1991; and (2) returning in November to drill a 3.85-inch core hole deviated out of the previous wellbore at 6868 feet and extending to 7588 feet. Ultimate depth of the well is planned to be 20,000 feet, or at a bottomhole temperature of 500{degrees}C, whichever comes first. Total cost of this drilling phase was approximately $2.3 million, and funding was shared about equally between the California Energy Commission and the Department of Energy. Phase II scientific work will commence in July 1992 and will be supported by DOE Office of Basic Energy Sciences, DOE Geothermal Division, and other funding sources.
Recently, significant progress has been made in using finite-difference analysis cod es to simulate the responses of complex structures due to direct lightning. Advances have been made in interfacing a finite-difference code with commercial computer aided design tools, in suppressing a weak instability associated with the thin-wire algorithm for modeling conductors much smaller than a cell size, and in visualizing the results with color movies. Preliminary comparisons between the results of the finite-difference code and the results obtained during a recent rocket-triggered lightning test are also presented.
Sandia National Laboratories and ICI Explosives USA have worked together since 1987 to develop computer modeling techniques for Rock Blasting. A result of this effort is the computer program DMC (Distinct Motion Code) which was developed for two-dimensional simulation of rock motion following a blast (Taylor and Preece, 1989 1992). This program has been used to study blasting-induced rock motion resulting from oil shale mining and has been coupled with a gas flow computation capability for better treatment of the explosive behavior. This past year it has been customized for simulations of bench blasting in coat mines and rock quarries (Preece and Knudsen, 1992b). The explicit descretized nature of DMC gives it an advantage over previous blast modeling programs because subtle differences, such as row delay timing, have an influence on the results. This paper will present a DMC study of the influence on percent cast of row delay timing in a typical coal mine bench blast.
The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, consisting of underground shafts, drifts, and ramps, and the accompanying surface pad facility and roads. The information in this report addresses the following topics: (1) a discussion of the potential effects of surface construction water on repository-performance, and on surface and underground experiments; (2) one-dimensional numerical calculations predicting the maximum allowable amount of water that may infiltrate the surface of the mountain without affecting repository performance; and (3) two-dimensional numerical calculations of the movement of that amount of surface water and how the water may affect repository performance and experiments. The results contained herein should be used with other site data and scientific/engineering judgement in determining controls on water usage at Yucca Mountain. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document for the Yucca Mountain Site Characterization Project.
The focus of this paper is on changes in perceptions of the risks associated with nuclear waste management over time. In particular, we are interested in the kinds of change that take place when the management programs, and those who are charged with implementing them, are subject to intensive public debate over an extended period of time. We are undertaken an over-time study of perceived risks in Colorado and New Mexico by implementing sequential random household surveys in each state, timed at six month intervals. This study employs three of these surveys, spanning the period from summer, 1990 to summer, 1991. Using these data, we examine the dynamics that may underlie variations in perceived risks over time. In particular, our analysis is focused on changes in the roles played by (1) basic political orientations (i.e. political ideology) and (2) trust in those who advocate conflicting policy positions.
Midway Valley, located at the eastern base of the Yucca Mountain in southwestern Nevada, is the preferred location of the surface facilities for the potential high-level nuclear waste repository at Yucca Mountain. One goal in siting these surface facilities is to avoid faults that could produce relative displacements in excess of 5 cm in the foundations of the waste-handling buildings. This study reviews existing geologic and geophysical data that can be used to assess the potential for surface fault rupture within Midway Valley. Dominant tectonic features in Midway Valley are north-trending, westward-dipping normal faults along the margins of the valley: the Bow Ridge fault to the west and the Paintbrush Canyon fault to the east. Published estimates of average Quaternary slip rates for these faults are very low but the age of most recent displacement and the amount of displacement per event are largely unknown. Surface mapping and interpretive cross sections, based on limited drillhole and geophysical data, suggest that additional normal faults, including the postulated Midway Valley fault, may exist beneath the Quaternary/Tertiary fill within the valley. Existing data, however, are inadequate to determine the location, recency, and geometry of this faulting. To confidently assess the potential for significant Quaternary faulting in Midway Valley, additional data are needed that define the stratigraphy and structure of the strata beneath the valley, characterize the Quaternary soils and surfaces, and establish the age of faulting. The use of new and improved geophysical techniques, combined with a drilling program, offers the greatest potential for resolving subsurface structure in the valley. Mapping of surficial geologic units and logging of soil pits and trenches within these units must be completed, using accepted state-of-the-art practices supported by multiple quantitative numerical and relative age-dating techniques.
Sandia National Laboratories (SNL) is a Department of Energy multiprogram engineering and scientific facility with unique design, development, and test capabilities arising from their work in nuclear weapons, energy resources, defense systems, nuclear safeguards, and specialized scientific endeavors. To support these programs, they have developed instrumentation and telemetry expertise not available elsewhere. This technology is applicable to projects in government and industry. Since the 1950s, they have applied our technical competence to meet difficult challenges with innovative solutions to data acquisition and telemetry problems. Sandia - with experience in fields as diverse as parachute design and plasma physics, geology and rocket guidance, human factors and high-speed aerodynamics, non-destructive testing and satellite communications - can use the power of synergism among our many disciplines to solve your complex problems of data and acquisition and analysis. SNL solves difficult data acquisition problems for extreme environments with expertise in advanced telemetry techniques, high data rate telemetry design, specialized electronics packaging, MIL-STD-1553 communications, instrumentation development, real-time data analysis, project management, specialized testers and data encryption.
